In general, offset printing is gaining attention as a method of mass producing electronic devices, such as Radio Frequency Identification (RFID) devices, polymer transistors, flexible displays, and solar cells. Such offset printing is suitable for mass production due to fast printing speed, since printing on printing sheets can be continuously and repeatedly performed by an engraving roll while the roll rotates.
FIG. 1 is a diagram showing an example of an offset printing apparatus of the related art.
Referring to FIG. 1, the offset printing apparatus of the related art generally includes an unwinder 2, which supplies a printing sheet 1, at least one printer 3, which prints electronic elements on the printing sheet 1, and a rewinder 4, which rewinds the printing sheet 1 after the printing by the printer 3 is completed.
In such an offset printing apparatus of the related art, since the unwinder and the rewinder are arranged in-line, the overall volume of the apparatus is increased, and the distance between the unwinder and the rewinder is long, thereby causing the printing sheet to become detached or making it difficult to maintain a desired amount of tension. This results in very strict design requirements, including the installation of control devices. Therefore, problems of high manufacturing costs and low productivity result.